You might look at Answer Set Programming, based on stable model semantics, which has both:

Baral, Chitta. 2003. Knowledge Representation, Reasoning, and Declarative Problem Solving. Cambridge University Press. Cambridge, UK.

Gelfond, Michael. Leone, Nicola. 2002. "Logic Programming and Knowledge Representation: The A-Prolog Perspective." Artificial Intelligence. 138(1-2):3-38.

Niemel, I. Simons, P. 1997. "Smodels: An Implementation of the Stable Model and Well-Founded Semantics for Normal Logic Programs." Proceedings of the 4th International Conference on Logic Programming and Non-Monotonic Reasoning. Dagstuhl, Germany. Springer-Verlag. 420-429.

_____________________________________________ Dr. Leo Obrst The MITRE Corporation, Information Semantics lobrst(a)mitre.org Information Discovery & Understanding, Command and Control Center Voice: 703-983-6770 7515 Colshire Drive, M/S H305 Fax: 703-983-1379 McLean, VA 22102-7508, USA

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From: owner-ciao-users(a)clip.dia.fi.upm.es on behalf of Alan H. Bond Sent: Sun 7/29/2007 3:22 PM To: ciao-users(a)clip.dia.fi.upm.es Subject: logic programming with naf and true negation

Do you know of anyone working on an extension of Prolog to include true negation in addition to negation as failure?

Alan Bond

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